Vacuum brake



April 175, 1930. Q FARMER 1,754,229

VACUUM BRAKE Fled F'eb. 14, 1928 INVENTOR CLYDE C. FARMER v ATTORNEY Patented Apr. 15, 1930 UNETED STATES PATENT @FFE CLYDE C. FARMER, OF PITTSBURGH, PENNSYLVANIA, ASSIG-NOR T THE WESTING- HOUSE AIR :BRAKE COMPANY, GF W'IL'IERDING, EENNSYLVANA, A CORPORATION 0F PENNSYLVANIA VACUUM BRAKE Application le. February 1/1, 1928.

This invention relates to brakes, and more particularly to a vacuum brake adapted for automotive vehicles.

It has heretofore been proposed to utilize the partial vacuum created in the intake manifold of an internal combustion engine for operating the brakes on a motor vehicle.

Ordinarily, when the brakes are to be appliec the engine throttle is shifted to its idling position, in which a minimum flow of air and fuel mixture is supplied to the engine manifold. Such being the case, when, in applying the brakes, the brake cylinder is connected to the intake manifold of the engine,

the 110W of air from the brake cylinder to the manifold may so weaken the mixture of air and fuel in the manifold as to cause the en ine to stall.

ne object of my invention is to provide means operated upon applying` the brakes for supplying additional fuel to the intake mani fold of the engine.

Another object of my invention is to provide means operated upon applying the brakes for supplying additional fuel to the manifold and adapted to prevent supply of additional fuel except when the brakes are applied.

Other objects and advantages will appear in the following more detailed description of the invention.

In the accompanying drawing, the single figure is a diagrammatic view, partly in section, of an apparatus embodying my invention.

The reference numeral 1 indicates the usual pipe leading from the carburetor 2 to the intake manifold (not shown) of an internal combustion engine, the pipe 1 containing the usual throttle valve 3 and the carburetor hav ing the usual air intake pipe Il and fuel supply pipe 5.

A brake cylinder 6 is provided containing piston 7 which is connected t-o rod 8, through which the vehicle brakes are applied and released. The chamber at one side of the pirton 7 is open to the atmosphere through port 9 and the chamber at the opposite side of the piston is connected through a pipe 1G with a Serial No. 254,197.

casing 11, shown as associated with the carburetor 2.

A plug 12 having a cone-shaped end portion 13 is screwed into the casing 11 and said plug is provided with a passage 1d which opens at one end into the fuel supply passage of the carburetor and entends centrally through the cone-shaped portion 13. The casing 11 is provided with a cylindrical bore containing a piston 15 having a depending stem 1G, the end of which is adapted to engage the small end of the cone-shaped portion 13 and when so engaging, to cutofi iiow of fuel through passage 11i.

rihe portion 13 extends into a cone-shape( chamber 17 of the casing 11 and said chamber is connected to pipe 10, the portion 13 extending into chamber 18, so as to form an annular outlet from chamber 1T to chamber 18. The chamber 19 at the opposite side of piston 15 is connected by a pipe 2O to a controlling valve device comprising a casing 21, containing a valve 22. A pipe 23 connects the valve device with the intake pipe 1 and the valve 22 is provided with a three way passage 24C which is adapted in one position of the valve to connect pipe with an atmospheric port 25 and in another position to connect pipe 20 with pipe 23, a handle 26 being provided for operating the valve 22. A plurality of grooves 27 are provided in the cylinder wall, which are adapted when the piston 15 moves upwardly to connect chamber 18 with chamber 19 and when the piston is in its normal position, as shown in the drawing, to cut oif communication between said chambers.

A. by-pass passage 28 is provided in the casing 11, which connects chamber pipe 10 with chamber 19 and interposed in. said passage is a ball check valve 29 for preventing back flow from pipe 10 to chamber 19.

1n operation, when it is desired to eect an application of tie brakes, the handle 26 is turned so as to operate the valve 22 and shift same to a position in which pipe 20 is connected to pipe 23 through passage 24. The chamber 19 is thus subjected to the partial vacuum existing in the intake pipe 1 and the lchamber `18 containing air at atmospheric from chamber 18 to chamber 19. Air at at-V mospheric pressure in the brake cylinder 6 is then vented through pipe 10 and the chamber 17 to chamber 18 and passes through the grooves 27 to chamber 19 and thence through pipe 20, passage 24 in valve 22, and pipe 23 to the intake pipe 1.

The brake cylinder piston 7 is then moved toVV the right by atmospheric pressure acting on the left side of the piston and the brakes are applied by movement of the rod 8.

The upward movement of piston 15 causes the end of the stem 16 to lift from its seat, permitting liquid fuel to flow through passage 1d to chamber 18, the flow being'accellrated by the action of the air current passing out of chamber 17 through the annular outlet to chamber 18.

Air flowing from the brake cylinder 6 to the intake pipe 1 is thus charged with atomized fuel and should the throttle valve 3 be in its idling position, the minimum flow of air and fuel mixture passing the throttle valve 3 willinot be made lean by flow of air from the brake cylinder to the intake pipe and consequently danger of stalling the engine will be obviated.

In order to release the brakes, the valve 22 is turned to release position, in which pipe 2O is connected through passage 24 with atmospheric port 25. Air from the atmosphere then flows to chamber 19 and thence through the by-pass passage 28, past check valve 29 tothe brake cylinder 6. Atmospheric pressure being thus reestablished upon opposite sides of piston 7, the usual brake release springs (not shown) operate to effect the release of the brakes and the release movement of piston 7.

Atmospheric pressure vbeing also established on opposite sides of piston 15, said piston is moved by gravity to its position in which the stem 16 seats on the end of the plug 13, so that flow of liquid fuel to chamber 18 is prevented.

The seating of stem 16 prevents any flow of fuel to chamber 18, except when the brakes are being applied and air is flowing from the brake cylinder to the intake manifold at a suflicient rate to maintain a differential pressure on piston 15, so that in the usual running of the vehicle, the operation of the carburetor 2 to supply the desired mixture of fuel and air is not disturbed.

Vhile one illustrative embodiment of the invention has been described in detail, it is not my'intention to limit-its scope to that.

, ters Patent, is

ated by the reduced pressure in the intake manifold of an internal-combustion engine for applying the brakes,'of means for connecting said element to the manifold, a member for controlling a communication for supplying motor fuel to the air passing from said element to the manifold, and a piston operated by the reduced pressure in the manifold for actuating said member to open said communication.

2. The combination with an element actuated by the reduced pressure in the intake manifold of an internal combustion engine for applying the brakes, of means for connecting said element to the manifold, a piston operated by the reduced pressure in the manifold for opening communication through which air is supplied from said element to the manifold, and means operated by said piston for supplying motor fuel to the air passing from said element to the manifold.

3. In a vacuum brake, the combination with a brake cylinder having a piston operated by reducing the fluid pressure on one side for applying the brakes, of a movable abutment having one side connected to said brake cylinder, means for connecting the opposite side of said abutment to the intake manifold of an internal combustion engine.

said abutment being operated by the reduced :.f

pressure in the manifold for opening communication from the brake cylinder to the manifold, and means operated by said abutment for opening communication through which motor fuel is supplied to the air passing from ,the brake cylinder' to the manifold. In testimony whereof I have hereunto set my hand. l Y

. CLYDE C'. FARMER. 

